1. Field of Invention
This invention relates to an apparatus for the crushing of solid materials such as rock or stone. In particular, this invention relates to rock and stone crushers which use two sets of cutting blades within the same crushing chamber for reducing large rocks or stones to usable sizes in one continuous operation.
2. Prior Art
Stone or rock mined from quarries is generally of a size which is unusable for common applications such as road building. These large pieces of rock or stone are usually broken down into usable sizes by rock crushers. The more useful sizes of stone are usually from about 1/2 inch to about 2 inches.
Many conventional rock crushers are available which will reduce rock or stone from large size rock to a usable size rock. For example, U.S. Pat. No. 3,784,117 discloses a rotary impact crusher comprised of impact bars secured within a rock crusher by wedge members. The impact bars fling the rocks or stones which are placed within the rock crusher against impact plates, said action resulting in the breaking of the stone or rock.
One of the deficiencies of conventional impact or rock crushing devices is their inability to take large size rocks and crush them to a consistently small size in a short period of time since conventional crushers contain only a single crushing mechanism within the crushing mill. As a partial answer to this deficiency, U.S. Pat. No. 4,046,325 discloses an apparatus for crushing rock, stone and like material which comprises a primary rotary impactor chamber and a secondary hammermill crushing chamber. In this device the first chamber contains a conventional rotary impactor wherein the rocks are impelled against triangular-shaped formations to break them up into smaller sized stones. The rocks reduced in size by the action of the rotary impactor are then transferred into a passageway. If the crushed material is of sufficiently small size, it exits through a discharge opening. However, if it is still too large, it will fall into a hammermill chamber where the rocks are further reduced in size by a hammermill crusher.
A somewhat similarly designed, two chamber apparatus for the comminuting of grain is disclosed in U.S. Pat. No. 3,595,290. The '290 patent discloses a double rotary, high velocity rotation mechanism.
While these double action rotary stone crushers or grain pulverizers are useful, a two chambered crushing device is necessarily inefficient and costly for the production of the proper size stone or grain. Further, neither of these devices discloses a two step crushing device contained in a single crushing chamber. A single chamber crushing device has substantial advantages over two chamber crushing devices since the crushing process would produce less dust and crush more rock, and the device would be less expensive to manufacture and easier to replace parts that have been damaged. In addition, since there would be two sets of cutting blades, the speed at which the machine would need to run to crush similar amounts of rock or stone could be reduced, thus reducing the wear and tear on the cutting bars and blades of the crushing device.
Therefore, it is an object of this invention to produce a solid material crushing device which is more efficient than prior art crushing devices.
It is another object of this invention to produce a stone crushing device which provides for more than one set of cutting blades within a single crushing chamber.
It is a still further object of this invention to produce a rock crusher which will produce more usable size rock and less dust than conventional rock crushers.
It is a still further object of this invention to produce a rock crusher with cutting blades which are easily replaceable and adjustable for producing rock or stone of a predetermined size.
It is a still further object of this invention to produce a two step rock crusher contained within a single crushing chamber.
These and other objects and features of the present invention will become apparent to those skilled in the art from a consideration of the following detailed description, drawings and claims. The description along with the accompanying drawings provides a selected example of construction of the device to illustrate the invention.